The quality, consistency, and cost of machined products depend on a complex combination of the performance of process steps and equipment. Manufacturing of complex, high-value products typically require lengthy trial-and-error procedures and result in wasted resources due to inconsistencies and/or uncertainties in material properties and/or behavior of manufacturing equipment under various manufacturing conditions. These inconsistencies or uncertainties, at least in part, result from the adverse effects caused by environmental conditions, e.g., contaminants, that may be introduced or generated during the manufacturing process. Furthermore, contaminants such as micro/nano-scale aerosol particles (<100 nanometers to a few micrometers) can also increase health risks to operators in a fabrication facility.
Within a typical semiconductor fabrication facility (FAB) environment, contaminants can be generated in the form of gases, chemical vapors, micro/nano-scale aerosol particles, airborne molecular contamination, etc. Micro/nano-scale aerosol particles containing a variety of ionic species in a cleanroom may arise from a number of sources including human behavior (e.g., hygiene, clothing, etc.), cleanroom airflow, equipment, materials, and nanomaterials synthesis processes. They can be either released directly or formed during atmospheric chemical reactions, such as for instance from evaporating heated chemicals/solvents, and gas leakage/outgassing from thin film and its processing equipment, etc. In addition to micro/nano-scale aerosol particles, airborne molecular contamination (AMC) is also a concern during semiconductor manufacturing processes. Such organic contamination may cause adverse effects on production tools and consequently increase costs for FAB operators. The AMC level in cleanroom environments is predominately created by internal sources of solvents and acetic acid, re-entrainment of exhaust air, aromatic compounds, as well as material outgassing. In addition, spills, leaks and mishandling can occur and can cause serious costs in terms of wafer loss and tool-down time.
A contamination-free manufacturing environment is desirable and can be achieved by source control/monitoring in combination with filtration solutions in air handling systems. Continuous, online, and real-time monitoring of these contaminant levels helps identifying sources, stabilizes production and prevents unexpected shortfalls of the service life of filtration units. Traditional environmental monitoring in a FAB environment, however, is expensive and time consuming, relying on a deployment of human-power for sample collection and dedicated equipment for measurement/characterization. Additionally, traditional environmental monitoring techniques do not provide continuous real-time monitoring, which means that when measurement results are provided for review, the condition of the FAB facility may have already changed.
In addition to monitoring contaminants (e.g., types and levels) in the cleanroom, close supervision and observation of operators and other persons, including visitors and third-party contractors, who enter in and out of a FAB facility, is also necessary. Traditional observational surveillance methods are typically implemented using stationary cameras located at predetermined locations within the facility. Installing a large number of cameras to achieve adequate coverage, however, can be very costly. Furthermore, although this traditional method can detect unauthorized persons or activities, it does not provide opportunities to detect unauthorized communications, such as video/picture recording, voice communication, and file uploads/downloads.
Therefore, there exists a need for an easier, faster and cheaper technology to realize a real-time monitoring of environment contaminant levels and security in a semiconductor fabrication facility.